The effect of motilin agonist ABT-229 on gastro-oesophageal reflux, oesophageal motility and lower oesophageal sphincter characteristics in GERD patients

Should video laryngoscopy or direct laryngoscopy be used for adults undergoing endotracheal intubation in the pre-hospital setting? A critical appraisal of a systematic review

The safety and utility of endotracheal intubation by paramedics in the United Kingdom is a matter of debate. Considering the controversy surrounding the safety of paramedic-performed endotracheal intubation, any interventions that enhance patient safety should be evaluated for implementation based on solid evidence of their effectiveness. A systematic review performed by Hansel and colleagues (2022) sought to assess compare video laryngoscopes against direct laryngoscopes in clinical practice. This commentary aims to critically appraise the methods used within the review by Hansel et al (2022) and expand upon the findings in the context of clinical practice.

The effects of camicinal, a novel motilin agonist, on gastro-esophageal function in healthy humans-a randomized placebo controlled trial

BACKGROUND

A proportion of patients with foregut dysmotility fail to respond to standard interventions. Motilin agonists may be beneficial in this group. We aimed to determine the effect of camicinal, a novel motilin agonist, on gastrointestinal physiology in healthy volunteers.

METHODS

Healthy male subjects were randomly assigned to receive a single dose of 125 mg camicinal or placebo in a double-blind cross-over design. Esophageal function and reflux indices were assessed using high-resolution manometry (pre and 1.5-h post dose) and 24-h ambulatory multichannel intraluminal impedance/pH. After a standardized meal, subjects ingested a wireless motility capsule from which compartmental transit times and motility indices were derived. Subjects were restudied with the alternate intervention after 7 days.

KEY RESULTS

The study subjects (12 male, mean age 47.4 years, range 22-55) tolerated the drug well, except one who exhibited mild abdominal pain on both placebo and camicinal. In comparison to placebo, gastric emptying time (GET) was accelerated following camicinal (-115.4 min, 95% confidence interval -194.4, -36.4, p = 0.009). No effect was demonstrable on esophageal function, small bowel, colonic, or whole bowel transit times and motility indices. With camicinal, as part of a post hoc analysis, there was a trend association between the percentage reduction in GET and total number of acidic reflux events (r = 0.56, p = 0.09).

CONCLUSIONS & INFERENCES

Camicinal decreases GET and was generally well-tolerated. In health, the direct effects of camicinal are on accelerating GET with a potential secondary benefit of reducing reflux events, which warrant further exploration in patient cohorts.

Buspirone, a new drug for the management of patients with ineffective esophageal motility?

Ineffective esophageal motility (IEM) is the most frequently encountered esophageal motility disorder. Patients may present with a variety of symptoms, such as dysphagia, heartburn, odynophagia, and regurgitation. Over the past years, the landscape of esophageal motility testing has been revolutionized; however, our current treatment options for IEM still remain limited. Previous studies have suggested that buspirone, a serotonin receptor agonist, enhances esophageal peristalsis and lower esophageal sphincter (LES) function. Recent work provides the first evidence that buspirone may influence LES resting pressure in patients with systemic sclerosis. Future research should evaluate whether the beneficial effects of buspirone also apply to the broad clinical entity of esophageal dysphagia patients with IEM.

Short-term treatment with proton pump inhibitors, H2-receptor antagonists and prokinetics for gastro-oesophageal reflux disease-like symptoms and endoscopy negative reflux disease

BACKGROUND

Approximately 25% of adults regularly experience heartburn, a symptom of gastro-oesophageal reflux disease (GORD). Most patients are treated empirically (without specific diagnostic evaluation e.g. endoscopy. Among patients who have an upper endoscopy, findings range from a normal appearance, mild erythema to severe oesophagitis with stricture formation. Patients without visible damage to the oesophagus have endoscopy negative reflux disease (ENRD). The pathogenesis of ENRD, and its response to treatment may differ from GORD with oesophagitis.

OBJECTIVES

Summarise, quantify and compare the efficacy of short-term use of proton pump inhibitors (PPI), H2-receptor antagonists (H2RA) and prokinetics in adults with GORD, treated empirically and in those with endoscopy negative reflux disease (ENRD).

SEARCH METHODS

We searched MEDLINE (January 1966 to November 2011), EMBASE (January 1988 to November 2011), and EBMR in November 2011.

SELECTION CRITERIA

Randomised controlled trials reporting symptomatic outcome after short-term treatment for GORD using proton pump inhibitors, H2-receptor antagonists or prokinetic agents. Participants had to be either from an empirical treatment group (no endoscopy used in treatment allocation) or from an endoscopy negative reflux disease group (no signs of erosive oesophagitis).

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

Thirty-four trials (1314 participants) were included: fifteen in the empirical treatment group, fifteen in the ENRD group and four in both. In empirical treatment of GORD the risk ratio (RR) for heartburn remission (the primary efficacy variable) in placebo-controlled trials for PPI was 0.37 (two trials, 95% confidence interval (CI) 0.32 to 0.44), for H2RAs 0.77 (two trials, 95% CI 0.60 to 0.99) and for prokinetics 0.86 (one trial, 95% CI 0.73 to 1.01). In a direct comparison PPIs were more effective than H2RAs (seven trials, RR 0.66, 95% CI 0.60 to 0.73) and prokinetics (two trials, RR 0.53, 95% CI 0.32 to 0.87).In treatment of ENRD, the RR for heartburn remission for PPI versus placebo was 0.71 (ten trials, 95% CI 0.65 to 0.78) and for H2RA versus placebo was 0.84 (two trials, 95% CI 0.74 to 0.95). The RR for PPI versus H2RA was 0.78 (three trials, 95% CI 0.62 to 0.97) and for PPI versus prokinetic 0.72 (one trial, 95% CI 0.56 to 0.92).

AUTHORS' CONCLUSIONS

PPIs are more effective than H2RAs in relieving heartburn in patients with GORD who are treated empirically and in those with ENRD, although the magnitude of benefit is greater for those treated empirically.

Weak and absent peristalsis

BACKGROUND

Weak and absent esophageal peristalsis are frequently encountered esophageal motility disorders, which may be associated with dysphagia and which may contribute to gastroesophageal reflux disease. Recently, rapid developments in the diagnostic armamentarium have taken place, in particular, in high-resolution manometry with or without concurrent intraluminal impedance monitoring.

PURPOSE

This article aims to review the current insights in the terminology, pathology, pathophysiology, clinical manifestations, diagnostic work-up,and management of weak and absent peristalsis.

New pharmacologic approaches in gastroesophageal reflux disease

This article highlights current and emerging pharmacological treatments for gastroesophageal reflux disease (GERD), opportunities for improving medical treatment, the extent to which improvements may be achieved with current therapy, and where new therapies may be required. These issues are discussed in the context of current thinking on the pathogenesis of GERD and its various manifestations and on the pharmacologic basis of current treatments.

The role of delayed gastric emptying and impaired oesophageal body motility

Delayed gastric emptying in a variable proportion of patients with gastro-oesophageal reflux disease has been observed in most series, however a relationship between delayed gastric emptying and increased gastro-oesophageal reflux has not been convincingly demonstrated. Enhanced postprandial accommodation and delayed emptying of the proximal stomach have been described, but some controversy exists. Impaired primary peristalsis is often present especially in patients with oesophagitis and its prevalence increases with increasing severity of inflammatory mucosal lesions. Patients with gastro-oesophageal reflux disease often have defective triggering of secondary peristalsis independently of presence of oesophagitis. It is presently unclear if impaired oesophageal motility is a primary defect or an irreversible consequence of inflammation. Attempts at pharmacological improvement of impaired oesophageal motility have been so far disappointing. Patients with partially preserved neuromuscular structures need to be identified in order to select them for new prokinetic therapy.

Short-term treatment with proton pump inhibitors, H2-receptor antagonists and prokinetics for gastro-oesophageal reflux disease-like symptoms and endoscopy negative reflux disease

BACKGROUND

Approximately 25% of adults regularly experience heartburn, a symptom of gastro-oesophageal reflux disease (GORD). Most patients are treated empirically (without specific diagnostic evaluation e.g. endoscopy. Among patients who have an upper endoscopy, findings range from a normal appearance, mild erythema to severe oesophagitis with stricture formation. Patients without visible damage to the oesophagus have endoscopy negative reflux disease (ENRD). The pathogenesis of ENRD, and its response to treatment may differ from GORD with oesophagitis.

OBJECTIVES

Summarise, quantify and compare the efficacy of short-term use of proton pump inhibitors (PPI), H2-receptor antagonists (H2RA) and prokinetics in adults with GORD, treated empirically and in those with endoscopy negative reflux disease (ENRD).

SEARCH STRATEGY

We searched MEDLINE (January 1966 to November 2008), EMBASE (January 1988 to November 2008), and EBMR in November 2008.

SELECTION CRITERIA

Randomised controlled trials reporting symptomatic outcome after short-term treatment for GORD using proton pump inhibitors, H2-receptor antagonists or prokinetic agents. Participants had to be either from an empirical treatment group (no endoscopy used in treatment allocation) or from an endoscopy negative reflux disease group (no signs of erosive oesophagitis).

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

Thirty-two trials (9738 participants) were included: fifteen in the empirical treatment group, thirteen in the ENRD group and four in both. In empirical treatment of GORD the relative risk (RR) for heartburn remission (the primary efficacy variable) in placebo-controlled trials for PPI was 0.37 (two trials, 95% confidence interval (CI) 0.32 to 0.44), for H2RAs 0.77 (two trials, 95% CI 0.60 to 0.99) and for prokinetics 0.86 (one trial, 95% CI 0.73 to 1.01). In a direct comparison PPIs were more effective than H2RAs (seven trials, RR 0.66, 95% CI 0.60 to 0.73) and prokinetics (two trials, RR 0.53, 95% CI 0.32 to 0.87). In treatment of ENRD, the RR for heartburn remission for PPI versus placebo was 0.73 (eight trials, 95% CI 0.67 to 0.78) and for H2RA versus placebo was 0.84 (two trials, 95% CI 0.74 to 0.95). The RR for PPI versus H2RA was 0.78 (three trials, 95% CI 0.62 to 0.97) and for PPI versus prokinetic 0.72 (one trial, 95% CI 0.56 to 0.92).

AUTHORS' CONCLUSIONS

PPIs are more effective than H2RAs in relieving heartburn in patients with GORD who are treated empirically and in those with ENRD, although the magnitude of benefit is greater for those treated empirically.

New pharmacologic approaches in gastroesophageal reflux disease

This article highlights current and emerging pharmacological treatments for gastroesophageal reflux disease (GERD), opportunities for improving medical treatment, the extent to which improvements may be achieved with current therapy, and where new therapies may be required. These issues are discussed in the context of current thinking on the pathogenesis of GERD and its various manifestations and on the pharmacologic basis of current treatments.

Effect of atilmotin, a motilin receptor agonist, on esophageal, lower esophageal sphincter, and gastric pressures

BACKGROUND

Motilin, an endogenous gastrointestinal (GI) hormone, increases upper gastrointestinal tract motility and is associated with phase III of the gastric migrating motor complex. The motilin receptor agonist, atilmotin, at doses of 6, 30 or 60 microg intravenously (IV), increases the early phase of gastric emptying. Prior studies at higher doses of 100-450 microg IV demonstrated that some subjects developed noncardiac chest pain.

AIMS

The aim of this study is to determine the effects of atilmotin on esophageal, lower esophageal sphincter (LES), and gastric contractility and the development of esophageal-related symptoms.

METHODS

Ten healthy volunteers underwent esophageal manometry to study the effects of atilmotin on upper GI motility. Five subjects were studied on three separate days following administration of saline placebo and subsequent IV bolus dose of atilmotin (6, 30 or 150 microg). Another five subjects were studied at the highest dose (150 microg).

RESULTS

Atilmotin at 150 microg increased proximal gastric pressure by 6.5 mmHg (P = 0.001 compared with placebo). Atilmotin increased LES pressure at all studied doses; LES pressure increased from 24 +/- 2 mmHg following placebo injection to 34 +/- 4 mmHg following a 30 microg dose of atilmotin (P = 0.007). In the esophagus, atilmotin increased the percentage of failed swallows at the highest dose studied. Failed swallows increased from 17 +/- 7% following placebo injection to 36 +/- 7% following a 150 microg dose of atilmotin (P = 0.016). Atilmotin decreased distal esophageal contractile amplitude only at the highest dose studied, from 69 +/- 8 mmHg (placebo) to 50 +/- 5 mmHg following 150 microg atilmotin (P = 0.018). There were no serious adverse effects or episodes of chest pain with atilmotin.

CONCLUSIONS

Atilmotin affects esophageal, LES, and gastric motility. LES and gastric pressures were increased, whereas there was disruption of esophageal peristalsis characterized by lower amplitude and failed contractions.

Structure-activity relationships of 9-substituted-9-dihydroerythromycin-based motilin agonists: optimizing for potency and safety

A series of 9-dihydro-9-acetamido-N-desmethyl-N-isopropyl erythromycin A analogues and related derivatives was generated as motilin agonists. The compounds were optimized for potency while showing both minimal antibacterial activity and hERG inhibition. As the substituent on the amide was increased in lipophilicity the potency and hERG inhibition increased, while polar groups lowered potency, without significantly impacting hERG inhibition. The N-methyl acetamide 7a showed the optimal in vitro profile and was probed further by varying the chain length to the macrocycle as well as changing the macrocycle scaffold. 7a remained the compound with the best in vitro properties.

Advances in roles of prokinetic agents in the treatment of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is characterized by the reflux of gastric content into esophagus with or without histological changes. Pathogenesis of GERD is lower esophageal sphincter (LES) dysfunction, abnormal clearing capacity of refluxed materials, delayed gastric emptying and abnormal resistance of esophageal mucosa to gastric acid, but the primary upper gastrointestinal motility dysfunction is regarded as the most important factor in general. Therefore, prokinetic agents which can restore gastric motility with increasing of LES and esophageal motility have been developed and used frequently in the treatment of GERD. There are several prokinetic agents such as metoclopramide, domperidone, cisapride and mosapride that facilitate acetylcholine release from the enteric cholinergic neurons through a selective 5-HT₄ receptor agonistic action. It is considered that prokinetic agents have the same effect as H2 blocker in the treatment of patients with mild GERD. Additionally, it was reported that a combination therapy with prokinetic agents and proton pump inhibitors (PPI) or H2 receptor antagonists (H2RAs) is more effective than monotherapy in patients with severe GERD. This article reviews the recent advances in the role of prokinetic agents in the treatment of gastroesophageal reflux disease.

Short-term treatment with proton pump inhibitors, H2-receptor antagonists and prokinetics for gastro-oesophageal reflux disease-like symptoms and endoscopy negative reflux disease

BACKGROUND

Approximately 25% of adults experience heartburn, the cardinal feature of gastro-oesophageal reflux disease (GORD), at least monthly. The evaluation and treatment of patients with suspected GORD is associated with a substantial economic burden. Most patients are treated empirically (without specific diagnostic evaluation). They include a wide range of underlying oesophageal injury. The severity of oesophageal injury can only be established in those who have undergone upper endoscopy. Patients without visible damage to the oesophagus have been referred to as having endoscopy negative reflux disease (ENRD). The pathogenesis of ENRD as well as its response to treatment may differ from GORD with oesophagitis.

OBJECTIVES

Summarise, quantify and compare the efficacy of the short-term use of proton pump inhibitors (PPI), H2-receptor antagonists (H2RA) and prokinetics in adults with GORD, treated empirically and in those with endoscopy negative reflux disease (ENRD).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2005), MEDLINE (January 1966 to December 2005), EMBASE (January 1988 to December 2005).

SELECTION CRITERIA

Randomised controlled trials focussing on symptomatic outcome after short-term treatment for GORD using proton pump inhibitors, H2-receptor antagonists or prokinetic agents. Studies were included provided that participants could be classified in the empirical treatment group (no endoscopy used in treatment allocation) or in the endoscopy negative reflux disease group (no endoscopic signs of erosive oesophagitis).

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

Thirty-one trials (9457 participants) were included: fifteen in the empirical treatment group, twelve in the ENRD group and four in both. In empirical treatment of GORD the relative risk (RR) for heartburn remission (the primary efficacy variable) in placebo-controlled trials for PPI was 0.37 (two trials, 95% confidence interval (CI) 0.32 to 0.44), for H2RAs 0.77 (two trials, 95% CI 0.60 to 0.99) and for prokinetics 0.86 (one trial, 95% CI 0.73 to 1.01). In a direct comparison PPIs were more effective than H2RAs (seven trials, RR 0.66, 95% CI 0.60 to 0.73) and prokinetics (two trials, RR 0.53, 95% CI 0.32 to 0.87). In treatment of ENRD, the RR for heartburn remission for PPI versus placebo was 0.69 (seven trials, 95% CI 0.62 to 0.78) and for H2RA versus placebo was 0.84 (two trials, 95% CI 0.74 to 0.95). The RR for PPI versus H2RA was 0.78 (three trials, 95% CI 0.62 to 0.97) and for PPI versus prokinetic 0.72 (one trial, 95% CI 0.56 to 0.92).

AUTHORS' CONCLUSIONS

PPIs are more effective than H2RAs in relieving heartburn in patients with GORD who are treated empirically and in those with ENRD, although the magnitude of benefit is greater for those treated empirically.

Relationship between acceleration of gastric emptying and oesophageal acid exposure in patients with endoscopy-negative gastro-oesophageal reflux disease

OBJECTIVE

A delay in gastric emptying has been reported in patients with gastro-oesophageal reflux disease (GORD), but its role in increasing the number of reflux episodes is still debated. The aim of this study was to assess the relationship between acceleration of gastric emptying and gastro-oesophageal reflux in patients with endoscopy-negative GORD and pathological oesophageal acid exposure.

MATERIAL AND METHODS

Twelve patients (7 M, age range 24-65 years) underwent 6-h postprandial (2.1 MJ meal) combined gastric emptying by real-time ultrasonography and intra-oesophageal pH monitoring after cisapride (20 mg b.i.d.) and placebo for 3 days, on two separate occasions at least 7 days apart in double-blind randomized order. Gastric emptying after placebo was also measured in 12 healthy volunteers (7 M, age range 25-54 years).

RESULTS

In the patients' group, the area under the emptying time curve was greater (p<0.01), and half and total emptying times prolonged (p<0.01) compared to the healthy subjects, 115 min (mean)+/-6 (SEM) versus 86+/-6 and 232 min+/-16 versus 160+/-7, respectively. Cisapride accelerated both half- and total gastric emptying (p<0.02): -22 min (mean); -10 to -34 (95% CI) and -48 min; -10 to -85, respectively, decreased both percentage of time at pH < 4 (p<0.01) and number of reflux episodes (p<0.05). However, no relationship was found between changes in gastric emptying and in the reflux variables by linear regression analysis (R2<0.005).

CONCLUSION

The emptying rate of the whole stomach is not a major determinant of gastro-oesophageal reflux.

Effects of a 5-HT(4) receptor agonist on oesophageal function and gastro-oesophageal reflux: studies using combined impedance-manometry and combined impedance-pH

BACKGROUND

5-HT(4) receptor agonists are used as promotility agents of the stomach, small and large intestine. There is limited information on the influence of 5-HT(4) receptor agonists on oesophageal function and gastro-oesophageal reflux.

AIM

To evaluate the effects of tegaserod, a 5-HT(4) agonist on oesophageal function using impedance-manometry and postprandial reflux using impedance-pH monitoring.

METHODS

Twenty healthy volunteers were enrolled in a double-blind randomized three-period crossover placebo-controlled study. Impedance-manometry and impedance-pH monitoring after a refluxogenic meal were performed at baseline and after 2 days of dosing with tegaserod 6 mg b.d. or placebo. Multichannel intraluminal impedance-EM recorded pressure and bolus transit data during standardized swallows. Multichannel intraluminal impedance-pH monitoring recorded the number of 2-h postprandial acid and non-acid reflux episodes.

RESULTS

We found no significant difference in distal oesophageal amplitude when subjects received placebo (median 94.5; range: 53-243 mmHg) or tegaserod (93.6; 43-216 mmHg). Bolus transit time was similar during dosing with placebo (7.1; 5.3-9.4 s) and tegaserod (7.2; 5.9-11.1 s). We observed similar numbers of acid and non-acid reflux episodes during dosing with placebo (5; 0-15 and 3; 0-18, respectively) and tegaserod (2; 0-11 and 4; 0-19, respectively).

CONCLUSION

Tegaserod, a 5-HT(4) receptor agonist does not change oesophageal motility and gastro-oesophageal reflux parameters in healthy volunteers.

The effect of mosapride on esophageal motility and bolus transit in asymptomatic volunteers

GOALS

To evaluate the effect of mosapride, a selective 5-hydroxytryptamine-4 agonist, on esophageal motility and bolus transit in asymptomatic volunteers.

STUDY

Twenty healthy subjects participated in two experiments, 7 days apart, and we utilized a randomized, double-blind cross-over design with 3-day pretreatments of placebo or mosapride. All subjects underwent combined intraluminal impedance manometry.

RESULTS

There was no difference in the amplitude, the duration, and the esophageal peristaltic patterns between the two pretreatments. The lower esophageal sphincter (LES) pressure and the number of transient LES relaxations did not change after mosapride vs. placebo. However, the rate of complete bolus transit in liquid swallows was higher with mosapride pretreatment (92.2%) than with placebo (84.6%; P < 0.01). The total bolus transit time in all liquid swallows showed a tendency to shorten after mosapride treatment (P = 0.06). The liquid bolus transit became faster after mosapride, especially in manometrically ineffective liquid swallows (P < 0.01). The total bolus transit time for manometrically normal viscous swallows decreased after pretreatment with mosapride (7.7 seconds; range, 6.8-9.2) in comparison with placebo (8.1 seconds; range, 7.1-11.1; P < 0.05).

CONCLUSIONS

Mosapride increases the rate of complete bolus transit in the esophagus, and enhances esophageal bolus transit in asymptomatic volunteers.

Promotility medications--now and in the future

Gastrointestinal promotility drugs stimulate smooth muscle contractions to enhance gastric emptying and small and large bowel transit. Currently available drug classes with prokinetic properties include antidopaminergic agents, serotonergic agents, and motilin-receptor agonists. Due to moderate prokinetic effects, poor symptomatic responses and the presence of adverse effects, there is a clear need for new classes of prokinetics. Several newer prokinetic drugs and drug classes are currently under evaluation. Selecting candidate agents and designing the appropriate therapeutic trials is hampered by the lack of insight in the pathophysiology of motility-related symptoms. As gastrointestinal motor disorders are chronic, relapsing, and remitting disorders, it seems desirable that studies with candidate prokinetic drugs establish a long-term efficacy and not only short-term effects on gastrointestinal functions.

Emerging drugs for gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease is a common medical problem caused by the exposure of the distal oesophagus to gastric contents. Existing medical therapy is very effective, but symptomatic relief with acid suppressants is often delayed. Treatment focuses on the suppression of gastric acid rather than on the underlying pathophysiological abnormalities, such as transient non-swallow-related lower oesophageal sphincter relaxation. Current pharmacological developments concentrate on drugs with lasting acid suppression and a faster onset of action. Compounds interacting with the complex neuromuscular regulation of the gastro-oesophageal junction are also being developed and offer exciting prospects.

Short-term treatment with proton pump inhibitors, H2-receptor antagonists and prokinetics for gastro-oesophageal reflux disease-like symptoms and endoscopy negative reflux disease

BACKGROUND

Heartburn affects 25% of the adult population on a monthly basis and represents the core symptom of gastro-oesophageal reflux disease (GORD). Treatment is readily available and puts a large demand on healthcare budgets. A majority of GORD patients show no endoscopic abnormalities and in daily practice most patients are treated empirically.

OBJECTIVES

Summarise, quantify and compare the efficacy of the short-term use of proton pump inhibitors (PPI), H2-receptor antagonists (H2RA) and prokinetics in adults with GORD and endoscopy negative reflux disease (ENRD).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2003), MEDLINE (January 1966 to December 2003), EMBASE (January 1988 to December 2003).

SELECTION CRITERIA

Randomised controlled trials focussing on symptomatic outcome after short-term treatment for GORD using proton pump inhibitors, H2-receptor antagonists or prokinetic agents. Participants had to be classifiable in the empirical treatment group (no endoscopy used in treatment allocation) or in the endoscopy negative reflux disease group (no endoscopic signs of erosive oesophagitis).

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

Twenty-seven trials (8402 participants) were included: thirteen in the empirical treatment group, ten in the ENRD group and four in both. In empirical treatment of GORD the relative risk (RR) for heartburn remission in placebo-controlled trials for PPI was 0.37 (two trials, 95% confidence interval (CI) 0.32 to 0.44), for H2RAs 0.77 (two trials, 95% CI 0.60 to 0.99) and for prokinetics 0.86 (one trial, 95% CI 0.73 to 1.01). In a direct comparison PPIs were significantly (p < 0.05) more effective than H2RAs (five trials, RR 0.69, 95% CI 0.61 to 0.77) and prokinetics (two trials, RR 0.53, 95% CI 0.32 to 0.87). In treatment of ENRD, RR for heartburn remission for PPI versus placebo was 0.68 (six trials, 95% CI 0.59 to 0.78) and for H2RA versus placebo was 0.84 (two trials, 95% CI 0.74 to 0.95). The RR for PPI versus H2RA was 0.74 (three trials, 95% CI 0.53 to 1.03) and for PPI versus prokinetic 0.72 (one trial, 95% CI 0.56 to 0.92).

REVIEWERS' CONCLUSIONS

The findings in this review suggest that antisecretory drugs are effective in the empirical treatment of complaints likely to originate from GORD and in treatment of ENRD and furthermore that PPIs are superior to H2RAs in empirical treatment of typical GORD symptoms.

Progress with novel pharmacological strategies for gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease (GORD) is a chronic disorder characterised by an increased exposure of the oesophagus to intragastric contents. Currently, GORD symptoms are maintained under control with antisecretory agents, mainly gastric proton pump inhibitors (PPIs). Although impaired oesophageal motility may partly underlie the pathophysiology of GORD, the use of prokinetic agents has been found to be unsatisfactory. To date, novel pharmacological approaches for GORD are mainly related to the control of transient lower oesophageal sphincter (LOS) relaxations (TLOSRs). The majority of patients with GORD have reflux episodes during TLOSRs, which are evoked by gastric distension, mainly occurring after ingestion of a meal. Patients with reflux disease with normal peristalsis and without or with mild erosive disease could potentially benefit from anti-TLOSR therapy. This therapy might also be of value to treat some severe forms of esophagitis in combination with PPIs. GABA-B-receptor agonists are the most promising class of agents identified so far for TLOSR control. The GABA-B-receptor agonist, baclofen, is the most effective compound in inhibiting TLOSRs in humans. Since baclofen has several CNS adverse effects, novel orally available GABA-B agonists are needed for effective and well tolerated treatment of GORD. Endogenous or exogenous cholecystokinin (CCK) causes a reduction in LOS pressure, an increase in TLOSR frequency and a reduction in gastric emptying. In healthy volunteers and patients with GORD, loxiglumide, a selective CCK1-receptor antagonist, was found to reduce the rate of TLOSRs, although its effect on postprandial acid reflux may be modest. Orally effective CCK antagonists are not marketed to date. The anticholinergic agent atropine, given to healthy volunteers and patients with GORD, markedly reduced the rate of TLOSRs. Because of severe gastrointestinal (and other) adverse effects of anticholinergics, including worsening of supine acid clearance and constipation, it is unlikely that this class of drugs will have a future as anti-TLOSR agents on a routine basis. In spite of their effectiveness in reducing TLOSR rate, untoward adverse effects, such as addiction and severe constipation, currently limit the use of morphine and other opioid mu-receptor agonists. The same applies to nitric oxide synthase inhibitors, which are associated with marked gastrointestinal, cardiovascular, urinary and respiratory adverse effects. Animal studies provide promising evidence for the use of cannabinoid receptor 1 agonists, by showing potent inhibition of TLOSRs in the dog, thus opening a new route for clinical investigation in humans. A better understanding of TLOSR pathophysiology is a necessary step for the further development of novel drugs effective for anti-reflux therapy.

Review article: new pharmacological agents for the treatment of gastro-oesophageal reflux disease

Proton pump inhibitors, which act at the terminal point of acid secretion--the H+, K+-ATPase--are currently the most effective pharmacological treatments available for reflux disease. Despite the efficacy of the proton pump inhibitors, there is still potential for clinical improvement in gastro-oesophageal reflux disease pharmacotherapy. Faster onset of complete acid inhibition and improved duration of efficacy are two potential areas for improvement A number of novel pharmaceutical agents are currently undergoing clinical evaluation for the treatment of gastro-oesophageal reflux disease. These include transient lower oesophageal sphincter relaxation-reducing agents, serotonergic agents/prokinetics, potassium-competitive acid blockers, mucosal protectants, histamine H3 agonists and anti-gastrin agents. One or more of these drug groups may represent the future medical therapy for gastro-oesophageal reflux disease, should they prove effective in the clinical setting. This review summarizes the state of the art with these agents.

The effect of mosapride on oesophageal motor function and acid reflux in patients with gastro-oesophageal reflux disease

OBJECTIVE

To evaluate the efficiency of the 5-HT4 agonist and 5-HT3 antagonist mosapride, as compared with cisapride, on oesophageal acid reflux variables and oesophageal motor function in patients with chronic gastro-oesophageal reflux disease (GORD).

METHOD

Forty-one patients with proven GORD were included in a double-blind, randomised, double-dummy, three-way crossover study. All patients received mosapride 60 mg twice daily, mosapride 30 mg three times daily, and cisapride 20 mg twice daily for seven days in a randomised order, separated by a washout period of at least five days. Twenty-three patients underwent four combined ambulatory 24-h motility and pH recordings within two weeks before the start of treatment and on day seven of each treatment period. The remaining 18 patients underwent three ambulatory 24-h pH recordings only, i.e. on treatment day seven of each treatment period.

RESULTS

Mosapride had no significant effect on the total number of contractions in the oesophagus, or on the effectiveness, or possible effectiveness, of the propagations. Significant but numerically small effects on peristaltic durations and amplitudes were noted during both mosapride and cisapride treatment as compared with baseline values. The effect on acid reflux for both mosapride and cisapride was most pronounced for the duration of the longest reflux episode. The fraction of time with pH less than 4 was reduced by mosapride 30 mg three times daily in the supine position and by cisapride both totally and in the supine position. The number of reflux episodes was reduced significantly only by cisapride. Oesophageal clearance was reduced significantly by cisapride only in the supine position.

CONCLUSION

Mosapride had small but statistically significant effects, comparable to those of cisapride, on acid reflux variables and oesophageal motor function in patients with GORD.

Effects of ABT-229, a motilin agonist, on acid reflux, oesophageal motility and gastric emptying in patients with gastro-oesophageal reflux disease

AIM

The effect of ABT-229, a new macrolide with no antibacterial activity, on gastro-oesophageal reflux, oesophageal motility and gastric emptying in patients with gastro-oesophageal reflux disease was investigated.

METHODS

Twenty-one patients were treated with a placebo and ABT-229 (2.5, 5 or 10 mg b.d.) in a randomized, incomplete crossover study design. Ambulatory 24-h pH manometry was performed and gastric emptying was assessed by the 13C-octanoic acid breath test on the seventh day of treatment.

RESULTS

A significant decrease was found in the mean (+/- s.e.) percentage of reflux time (intra-oesophageal pH < 4) for ABT-229 5 mg b.d. and 10 mg b.d., but not for 2.5 mg b.d., compared with placebo. For ABT-229 5 mg, it was 8.5 +/- 0.5% vs. 10.7 +/- 0.7% (P < 0.038) and, for ABT-229 10 mg, it was 6.6 +/- 0.5% vs. 8.4 +/- 0.5% (P < 0.019). There were no significant differences in any of the analysed manometric parameters. In addition, the gastric half-emptying time for all doses of ABT-229 did not differ significantly from that after placebo.

CONCLUSIONS

ABT-229 is able to reduce slightly, but significantly, acid reflux in patients with gastro-oesophageal reflux disease. This effect does not appear to be due to a measurable improvement in oesophageal motility or gastric emptying.

Efficacy of a motilin receptor agonist (ABT-229) for the treatment of gastro-oesophageal reflux disease

BACKGROUND

ABT-229 is a potent motilin agonist without significant antibiotic activity. It has been shown to improve gastric emptying in humans and to increase lower oesophageal sphincter pressure in cats.

AIM

To assess the efficacy of four different doses of ABT-229 (1.25 mg, 2.5 mg, 5 mg, 10 mg b.d.) compared to placebo in the treatment of gastro-oesophageal reflux disease, and to determine its safety in patients with gastro-oesophageal reflux disease.

METHODS

In a double-blind, multicentre study, 324 patients with heartburn were randomized to receive four different doses of ABT-229 or placebo for 8 weeks. The efficacy was evaluated by Patient Symptom Questionnaire, daily diary, endoscopy and global evaluation of efficacy.

RESULTS

There were no statistically significant improvement scores for any of the ABT-229 treatment groups vs. the placebo group in any of the efficacy parameters. Reflux symptom scores were significantly worse after treatment in the dyspeptic group. ABT-229 appeared to be well tolerated and safe in total daily doses up to 20 mg.

CONCLUSION

ABT-229 appears to have limited, if any, clinical utility in the treatment of gastro-oesophageal reflux disease.

The effect of cisapride on oesophageal motility and lower sphincter function in patients with gastro-oesophageal reflux disease

OBJECTIVES

To evaluate the efficiency by which the 5-HT4 agonist cisapride affects important motor functions involved in the control of gastro-oesophageal reflux.

METHOD

Thirty patients with proven gastro-oesophageal reflux disease (endoscopy and 24 h pH-metry) were included in a randomized, double-blind, placebo controlled study with a cross-over design. Cisapride, 20 mg b.i.d., during 4 weeks was compared with placebo. At baseline, as well as after 4 and 8 weeks all patients underwent symptom assessments, sleeve manometry with concomitant oesophageal pH-monitoring and an acid clearance test.

RESULTS

Despite adequate plasma levels cisapride had no significant effect on swallow induced peristaltic amplitude, duration, propagation speed, the elicitation of secondary peristalsis nor on acid clearance. Neither the basal tone of the lower oesophageal sphincter nor the number of transient lower oesophageal sphincter relaxations induced by gas distension of the stomach was affected by the administered dose of cisapride.

CONCLUSION

Although cisapride has been alleged to improve symptoms as well as the oesophagitis in patients with gastro-oesophageal reflux disease, we found the compound (20 mg b.i.d.) devoid of effects on important motor mechanisms involved in the pathogenesis of the disease.

Central neurocircuitry associated with emesis

Ingestion of toxin, traumatic events, adverse drug reactions, and motion can all result in nausea and emesis. In addition, cyclic vomiting syndrome is quite prevalent in the pediatric population. Coordination of the various autonomic changes associated with emesis occurs at the level of the medulla oblongata of the hindbrain. Chemosensitive receptors detect emetic agents in the blood and relay this information by means of neurons in the area postrema to the adjacent nucleus tractus solitarius (NTS). Abdominal vagal afferents that detect intestinal luminal contents and gastric tone also terminate in the NTS (gelatinosus, commissural, and medial subnuclei). The NTS is viscerotopically organized into subnuclei that subserve diverse functions related to swallowing (subnucleus centralis), gastric sensation (subnucleus gelatinosus), laryngeal and pharyngeal sensation (intermediate and interstitial NTS), baroreceptor function (medial NTS), and respiration (ventrolateral NTS). Neurons from the NTS project to a central pattern generator (CPG), which coordinates the sequence of behaviors during emesis, as well as directly to diverse populations of neurons in the ventral medulla and hypothalamus. Thus, it is critical to realize that there is not an isolated "vomiting center," but rather groups of loosely organized neurons throughout the medulla that may be activated in sequence by a CPG. The newer antiemetic agents appear to block receptors in the peripheral endings of vagal afferents to reduce "perception" of emetic stimuli and/or act in the dorsal vagal complex. A primary site of action of 5-HT(3)-receptor antagonists is by means of the vagal afferents. Neurokinin-1 receptor (NK(1)R) antagonists are antiemetics, because they act at a site in the dorsal vagal complex. Part of their effectiveness may be the result of inhibition of the NK(1)R on vagal motor neurons to prevent fundic relaxation, which is a prodromal event essential for emesis. Delta(9)-tetrahydrocannabinol (Delta(9)-THC), the major psychoactive component of marijuana, can be therapeutically useful as an antiemetic. The site of action of Delta(9)-THC is on cannabinoid CB1 receptors in the dorsal vagal complex. However, it decreases fundic tone and antral motility. It is not easy to predict the potential antiemetic effects of drugs that alter motility. Although antiemetic drugs are available for management of acute chemotherapeutic-induced emesis, few treatments are effective for delayed emesis or cyclic vomiting syndrome.